Yes, NW Trails overlays the default mapset on the GPSMAP 66st (I have one and have been running the mapsets with no problems).

The next release of NW Trails will not have the new trails in your area unless they are reported and/or submitted by a user such as yourself. If you don't have GPS tracks of them, then I would need to know of a source for obtaining that data on them.

I'm fairly excited for this release, too! I've been using a touchscreen Oregon of some variety of flavor for the past several releases, but I'm liking the touchscreen functionality less and less. It's time to get back to buttons for me.

NW Trails/Topos should work fine on either model. I'm inclined to go with the st version since that includes a built-in DEM model, which allows for hillshading and elevation profiles of tracks that don't include elevation data.

I'm still plugging away at the mapset, but my available time for it has been drastically curtailed of late due to living/commute arrangements, travel, and classes. Please continue to contribute, as I have no intentions of dropping the project!

I definitely appreciate getting all tracks, even for those trails that seem to match up well already in the database. It helps me narrow down when changes *are* made to the trail, and lets me know the current state matches what's in the mapset.

The trails are identical (expect in places where I've neglected to tag data for inclusion in one mapset or the other).

NW Trails is useful as an overlay in other mapsets, such as the Garmin City Navigator maps. NW Topos is intended as a stand-alone set for off-road navigation.

As for overwriting your existing mapset, that is dependent on the GPS you have and the firmware it is running. It used to be that everything was given the same name (gmapsupp.img) and units could only recognize that name, so uploading a mapset would write over the existing one. Most of the newer Garmin units these days allow for the file to be named anything, and BaseCamp is smart enough to name the files based on the content being uploaded.

When uploading from BaseCamp, you have to be sure to do a "custom/partial" upload and only select the state tiles, making sure to NOT select the background tile. Otherwise, you will end up loading the non-transparent background map that is only there to make it easier to locate things when viewing the mapset on the computer. The default "complete" upload includes that background tile and prevents other loaded mapsets from displaying under the trails on the GPS.

As for uploading multiple/subsequent mapsets, I believe that BaseCamp is smarter than MapSource in that it gives each map a name based on the source map, so different uploads have different names and do not affect one another when coming from different source mapsets. With MapSource, everything is always uploaded with the same generic map name, so uploading a second mapset overwrites the first one.